Head lice and other parasites are a continuing health problem in many parts of the world, and methods for treatment have not been totally successful in eradicating the spread of this persistent nuisance. Known methods of treatment include combs for removing lice which are caught between the comb teeth when they are passed through the hair, but this approach tends to be inadequate in removing lice eggs, which remain attached to the hair and are harder to remove by this method. An example of this type of comb is given in U.S. Pat. No. 4,671,303 to Saferstein et al.
Another widespread and well known method for treatment of lice infestation is the use of chemicals, and these are divided into categories of those which are effective against lice only, and those which are effective against lice and their eggs. A problem with this method is the tendency of lice to build up resistance to the active ingredients in these chemicals, reducing their effectiveness. Accumulation of these chemicals in the body is detrimental to health, especially for children.
Grooming combs and brushes for animals which are designed to spread insecticidal ingredients are disclosed in U.S. Pat. Nos. 4,958,596 to Belan, 4,902,154 to Valenza, 4,862,832 to Metzner, 4,685,423 and 4,604,971 to Baker et al.
U.S. Pat. No. 5,067,444 to Parker discloses an animal grooming comb with a hair dryer. A comb for capturing insects on an animal's coat is disclosed in U.S. Pat. No. 4,815,232 to Rawski.
Hair and styling dryers for human hair are described in U.S. Pat. Nos. 3,894,547 to Scivoletto, and 3,814,898 to Levine. Neither of these patents relates to treatment of lice in hair.
Natural ingredients have also been used to treat lice infestation, including the use of aromatic oils. These materials are not more effective than chemicals, and have the tendency to cause severe irritation of the scalp in babies and young children.
An electronic device marketed by Mepro-Epilady under the tradename "Robi-Combi" has been introduced as another method of treating lice infestation. An electrically charged metal comb is passed through the hair, and a charged capacitor is discharged through lice contacting adjacent comb teeth. This method is limited by the need for the comb to physically contact each lice, and by its ineffectiveness against lice eggs.
The behavior of lice in the scalp has been scientifically studied and it is known that the head lice feed on human blood via the soft skin of the scalp. The lice attach themselves to the hair near the root at a distance of about 3 mm from the scalp, their heads facing downward toward the scalp. Every several hours the lice crawl toward the scalp skin, to suck blood, and when satisfied the lice return to the resting position, in which they remain most of time. In this position, the lice lay their eggs and attach them to the hair at a distance of about 6 mm from the scalp, and this distance grows about 1 mm per day with normal hair growth.
Lice and lice eggs are extremely sensitive to temperature; exposure to a temperature of 55 degrees C for 5 minutes kills them, and at 80 degrees C, exposure of only a few seconds kills them. While such high temperature exposure can be effective, however, the main problem with the application of high temperatures to the scalp is the risk of burning the scalp skin.
Therefore, it would be desirable to provide a lice comb which makes use of known temperature exposure characteristics for destruction of head lice and lice eggs, without presenting a danger of harm or irritation to the scalp.
It would also be desirable to provide a method of lice treatment using temperature, which is convenient and effective.